EXCEED THE SPACE PROVIDED. In this proposal, a renewal of our studies of the effects of ethanol on protein kinase C (PKC), we propose to investigate further our recent finding that PKC interacts with and is activated by members of the small GTP'ase Rho family of signaling proteins and that this effect is modulated by ethanol. The PKC family of kinases are involved in regulation of various signaling cascades and receptors, ion channels and lipid regulating enzymes in the cell, a feat achieved with high selectivity and localization due to the diversity of PKC isoforms each comprised of varying signaling modules. Likewise the Rho family of GTP'ase are involved in a wide array of key cellular processes from cytoskeletal remodeling to the control of nuclear transcription. The finding that these two major signal transduction controlling elements interact brings together diverse areas of cell signaling. Further it brings new possibilities for uncovering how ethanol impairs cell function in areas where both PKC and Rho-proteins are involved. Accordingly we propose to investigate the effect of ethanol on PKC-Rho-protein interactions according to the following aims: Aim 1 To determine the effect of ethanol on Rho-protein-induced PKC activity Aim 2 To investigate the effect of ethanol on PKC-Rho-protein binding and Rho-protein-membrane interactions Aim 3 To determine effects of ethanol on the PKC-induced changes of Rho-protein nucleotide bound state, GTP-binding and GTP'ase activities. Aim 4 To investigate the effect of ethanol on PKC-Rho-protein interactions involved in neurite extension and hepatic stellate cell activation